The invention relates generally to a refrigerator cabinet cooled by an absorption refrigerating apparatus and specifically to an automatic defrosting system for the refrigerator cabinet.
Refrigerator cabinets include a freezing compartment, refrigerated by an upper part of an evaporator, and a refrigerating compartment, refrigerated by a lower part of the evaporator. The operation of the refrigerating apparatus is controlled by a first means, which senses the temperature in the refrigerating compartment. The air in the freezing compartment is refrigerated by a fan circulating the air past the upper part of the evaporator. Such a refrigerator cabinet is described in U.S. Pat. No. 3,177,675. Its electrically driven fan is in operation when the refrigerating apparatus is in operation and is shut off when the evaporator is defrosted.
Such a cabinet has the drawback that, when the ambient temperature is low, say +10.degree. C., the demand for cooling in the refrigerating compartment, which for instance is maintained at a temperature of +3.degree. C., will decrease and the refrigerating apparatus will be shut off during periods that are longer than when the ambient temperature is higher. Thus, the flow of refrigerant through the evaporator will decrease causing the temperature in the freezing compartment to rise.
The object of the invention is to eliminate such a drawback and effectively control the temperature in the freezing compartment, not only for efficient cooling, but also for efficient automatic defrosting of the freezing compartment.